GEOMORPHOLOGY (EOLIAN)

Question 1

Desert

Answer 1

places with at most 25cm of precipitation
Of dry places in which yearly precipitation is less than the potential loss through evaporation

Question 2

Extremely Arid

Answer 2

12 consecutive months w/o rainfall

Question 3

Arid

Answer 3

<250mm annual rainfall

Question 4

Semi Arid

Answer 4

250-500 mm mean precipitation

Question 5

Deflation

Answer 5

actual removal of grains thus affecting only those unsconsolidated or loose ones

Question 6

Abrasion

Answer 6

polishing and scouring of rock surfaces

Question 7

Saltation

Answer 7

loose material remove from a bed and carried by air or water then return again to the surface

Question 8

Creep/Rolling

Answer 8

Large particles are too heavy to be lifted are rolled across the surface with the momentum gained from the impact of jumping san particles

Question 9

Suspension

Answer 9

Very fine grained dirt and dust are lifted into the wind

Question 10

Reptation

Answer 10

when grains in motion collide, they become more easiliy moveable at a lower wind velocity compared to the velocity needed to move them by wind alone

The process of saltating grains releasing splash-like shower of particles that make small hops from the point of impact

Question 11

Dust or stand storm

Answer 11

A meteorological Phenomenon that occurs in arid to semi-arid regions which arise when a gust form or other strong wind blows loose sand and dirt from a dry surface

Question 12

Dust or Sand Devils

Answer 12

smaller, brief whirldwind most frequent in the early afternoon when a land surface is heating rapidly

Question 13

Sedimentation

Answer 13

occurs simply when grains fall out of air or stop creeping forward

Question 14

Accretion

Answer 14

occurs when saltating grains hit the ground with such force that some grains come to rest where they strike

Question 15

Encroachment

Answer 15

Deposition that occurs on a rough surface creeping grains are held up while saltating one may move on

Question 16

Ventifacts

Answer 16

Cobbles or pebbles on stony desert surface often faceted due to wind abrasion

Question 17

Hamada

Answer 17

Rocky desert lag consist of corase rocks

Question 18

Desert Pavement or Reg

Answer 18

Surfaces covered by lag deposits

Question 19

Desert Varnish

Answer 19

Dark, surface patina of iron and mangangese oxides

Question 20

Lag deposits

Answer 20

thin veneers of gravel or coarser materials overlying finer ones

Question 21

Blowouts

Answer 21

commonest landforms produced by win erosion which are scoured depressions in weark unconsolidated sediments

Question 22

Pans

Answer 22

Closed depressesions that are common in dryland areas partly formed by deflation
Few meters wide only cm deep

Question 23

Yardangs

Answer 23

spectacular streamlined, sharp and sinuous ridges parallel to the wind and separated by parallel depressions

Question 24

Zeugen

Answer 24

Redisual blocks of rock produced by wind earting away strata esp. the soft ones close to the ground

Question 25

Loess

Answer 25

Wind-blown silt blankets

Question 26

Dunes

Answer 26

Mounds and ridges of sand from the winds bed load

Question 27

Aeolianites

Answer 27

Lithified wind blown carbonate deposits

Question 28

Erg

Answer 28

Sandy Deserts Or dry areas with large acummulation of sands

Question 29

Aeolian Ripples

Answer 29

small aerolian bedform with heights of less than a cm to more than ten cm

Question 30

Transverse Dunes

Answer 30

Straight crested forms aligned perpendicular to the prevailing uniformly wind direction

Question 31

Barachnoid

Answer 31

Long sysmmetrical dunes perpendicular to the prevailing wind Consist of joined barchans and looks like row of connected crescents Intermediate between tranvese and Barchan

Question 32

Barchan Dunes

Answer 32

Cresent shaped dunes perpendiculat to the dominant wind direction Tips/Points/ends or wings are curved downwind parallel to the wind direction and enclose the slip face

Question 33

Parabolic Dunes

Answer 33

Long axis is perpendicular to the wind Wings or points are curved upwind opposite to the direction of the wind Have multiple slip faces Occurs near coasts and in areas of vegetation

Question 34

Linear or Seif

Answer 34

two prominent wind direction at 90 deg to each other Corss bedding avalanching down both sides of the dunes Ridge is parallel to the wind while theres two opporiste slip face

Question 35

Star

Answer 35

Slip faces in many orientations hence cross bedding directions are also variable

Question 36

Draa

Answer 36

Sandy bedforms which are larger in magnitude than dunes reaching up to 400 m high and sit up to 4km spacing

Question 37

Zibar

Answer 37

corase grained bedform of low relief and possessing no slip face. also known as whaleback dunes

Question 38

Sand Sheets or Streaks or Stringer

Answer 38

Large bodies of sand with no discernible dune forms

Question 39

Dunefield

Answer 39

At least 10 dunes

Question 40

Nabkha

Answer 40

Vegetated Sand mound